The present invention relates to a resin molding machine and a method of resin molding, in each of which a molded product can be easily released from a resin molding die even if resin which can firmly stick to the resin molding die is used, contaminating the die can be prevented and a cleaning action can be easily performed.
These days, green resin, which does not badly influence the environment, has been used in resin molding machines. The green resin includes an organic phosphorous fire retardant, a hydrated fire retardant or no fire retardant. In comparison with conventional resin, the green resin can firmly stick to a molding face of a resin molding die. Therefore, it is difficult to release a product, which has been molded with the green resin, from the resin molding die. Further, the resin molding die is easily contaminated.
Conventionally, a release agent is mixed with resin so as to easily release a molded product from a resin molding die. For example, in case of producing automobile parts which must have high reliability, no release agent is included in resin for molding, so resin-molded parts cannot be easily released from the resin molding die and the resin molding die is easily contaminated.
In case of using transparent resin for encapsulating an LED, optical characteristics of the resin are important, so no release agent is included. Therefore, resin-molded products, e.g., LED, cannot be easily released from a resin molding die.
To easily release resin-molded products from a resin molding die, cavity faces of a resin molding die are mirror-finished or a release agent is applied to a molding face of a resin molding die.
To remove contaminations from a molding face of a resin molding die, the molding face is brushed every time a molding action is performed or an energy ray, e.g., ultraviolet ray, laser beam, is irradiated to the molding face for ashing and removing contaminations. Note that, a method of removing contaminations from a molding face by irradiating an excimer laser is disclosed in Japanese Patent Gazette No. 2003-145548.
Sticking contaminations onto a molding face is caused by resin and a structure of the molding face. For example, even if the molding face including cavities is formed by electric discharge machining and polished like a mirror face, micro holes and micro projections are complexly formed in the molding face. Therefore, resin fills the micro holes and the micro projections during the molding action. When the molding face is cleaned, the resin filling the micro holes and the micro projections must be removed.
The method of removing contaminations by irradiating an energy ray, e.g., ultraviolet ray, laser beam, is effective to clean the molding face. However, the molding face must be cleaned by the energy ray every time several hundred molding actions are performed, so a manufacturing line must be stopped for the cleaning action. Further, the cleaning action is troublesome. In case of cleaning the molding face by irradiating the excimer laser, the manufacturing line need not be stopped, but contaminations are decompounded and removed by an ozone gas, which is formed by irradiating the excimer laser. Namely, contaminations cannot be securely removed, and a harmful gas is formed.